Type 2 Diabetes Linked with Colorectal Cancer

A longer duration of obesity also increased risk of colorectal cancer for diabetic patients…

Dutch researchers have assessed the risk of colorectal cancer associated with type 2 diabetes, as compared with a nondiabetic reference population.

They conducted an observational population-based cohort study within the Clinical Practice Research Datalink (1987–2012). All patients (≥18 years) with at least one prescription for an antidiabetic drug (n = 300,039) were matched (1:1) by birth year, sex, and practice to a comparison cohort without diabetes. Cox proportional-hazards models were used to derive adjusted hazard ratios (HRs) for colorectal cancer associated with type 2 diabetes. Within the diabetic cohort, associations of colorectal cancer with treatment stages and duration of obesity (BMI ≥30) were studied.

After 4.5 years of follow up, a total of 2,759 cases of colorectal cancer were detected among the diabetic study population. The results demonstrated that type 2 diabetes was associated with a 1.3 fold increase in risk of colorectal cancer (HR 1.26 [95% CI 1.18-1.33]). Within the diabetic patients, there was no association found in the treatment stages. The duration of obesity of 4-8 years has demonstrated a statistically significant difference in risk of colorectal cancer (HR 1.19[1.06-1.34]) and >8 years (1.28[1.11-1.49]).

The authors concluded that type 2 diabetes is associated with a moderately increased risk of colorectal cancer. Within the diabetic patients, longer duration of obesity also showed increased risk of colorectal cancer.

Practice Pearls:

This study has demonstrated that risk of colorectal cancer increases with longer duration of obese type 2 diabetes patients.

More studies are necessary to determine whether the increased risk of colorectal cancer is reversible through weight loss.